Our sense organs 45

More documents

Recommendations

Info

Whispering 25 Spacious office 50 Motor car cruising smoothly 50 Thunder 65 Noisy street traffic 70 Typewriter 70 Waterfall 90 Freight train 98 Sawmill 100 Jet plane (at 600m height) 105 Disco 114 Prop-driven plane starting up 120 Boilermaking 120 Rock concert 125 Pneumatic drill 130 Artillery fire 130 Testing airplane engines 140 Jet engine starting up 1<strong>45</strong> Let us now consider the structure of the ear. The auricle: The human auricle, with its attractive relief of ridges, hollows, bulges, curves and grooves, is unmistakeably the same in its basic features, yet is a little different, in each one of us. The fact that these complex and beautiful forms play an important part in the hearing process has only been discovered in recent years. Sounds are conducted to the external hearing canal along two different paths, with the result that the sound travelling along the shorter route arrives one five thousandth of a second before the other signal. Given that sound travels at a speed of 330 m/s, this means that the difference in path length is about 6.5 cm. This is quite separate from the time difference between the two ears, which enables us to locate the source of various sounds. Such refined accoustic analysis is fairly essential for us. In effect we are able to analyse sounds in three dimensions, in such a way that we can recognise the direction of all incoming sounds, as well as the location and motion of their sources. Vocal communication requires very accurate identification of the position and movement of someone who is speaking, as well as of all the complex sound sequences involved. Since there are two sound paths for each ear, we virtually possess four ears. This ingenious system is so subtly and cleverly designed, that it all happens without us ever being aware of any doubling or quadrupling of sounds. Darwin’s book, The Descent of Man and Selection in Relation to Sex was published in 1871. In it he The organ of Corti Columnar cells Spiral ligament Epithelial cells of the scala tympani Supporting cells (of Hensen) Outer hair cells Interior tunnel Inner hair cells Internal spiral sulcus Pillar cells Cochlear nerve Bony spiral layer Edge of the bony spiral layer Tectorial membrane Vestibular membrane Cochlear duct
denigrated the external human ear, with all its convolutions, as being pointless and useless, a degenerate left-over from some alleged evolutionary history. The little protrusion on the upper outside edge of the auricle has been known since then as “Darwin’s tubercle”. Generations of researchers after Darwin blindly accepted his verdict on the ear. But in reality, the whole beautiful, convoluted labyrinth that is our auricle is a precise, genetically programmed device which delivers an identical additional signal to the brain after a time lag of one five thousandth of a second ( = 0.0002 s, see the diagram on page 24). In effect, one has four ears, two of which are located slightly higher than the other two. The result of this finely tuned system is that the brain is able to process six different values, two of them being the differences between the two upper ”ears”, two more are those between the two lower “ears”, and the third pair is that between the lower “ear” on one side, and the upper “ear” on the other side (see the diagram on page 25). The required computations are carried out at lightning speed in the brain to give us a very sophisticated “sound image” of our surroundings. This structure is also crucial in our astounding ability to voluntarily suppress some sounds to the enhancement of others. Middle ear: After travelling along the external acoustic meatus, incoming sound waves strike the ear drum, which is set vibrating. The energy transferred in this way is passed on, as the three tiny, connected bones in the middle ear (malleus, incus, and stapes, or hammer, anvil and stirrup) transmit the sound vibrations through the oval window into the inner ear. Weighing only about 10 mg, a tiny percent of the mass of the smallest of coins, these minute bones are the smallest in the entire human body. The hearing process involves the transfer of air vibrations into the liquid medium of the inner ear. In the normal course of events, the greater part of the sound energy would be reflected at an air/liquid boundary, and such losses would play havoc with the hearing process. To circumvent this, the Creator used a very ingenious interface structure which limits reflection losses to a negligible level. The cochlea Scala vestibuli Cochlear duct Scala tympani Sensory zone (organ of Corti) Vestibular membrane Helicotrema Round window Stapes in oval window This complex mechanism, comprising the ear drum and the three middle ear bones, exactly matches the sound wave impedance in air to that of the inner ear. The effective vibrational area of the ear drum is about 0.65 cm 2 , which is 20 times that of the oval window (only 0.032 cm 2 ). This is equivalent to an amplification factor of 20. In addition, the leverage afforded by the malleusincus-stapes linkup provides a further amplification factor of 3. Inner ear: It is clear that a massive amplification factor is involved in the conversion of air waves (at the ear drum) to the vibrations of the liquid in the cochlea. The inner ear, comprising both the balance organ and the cochlea (Latin cóchlea = snail), is housed in the solid bone of the skull. A second conversion takes place here; mechanical vibrations are changed into electric neural (nerve) impulses. The cochlear duct is filled with a highly viscous liquid (Latin viscum = birdlime, sticky, or thick), called the endolymph. There are two more liquidfilled spaces on either side, the scala vestibuli (Latin scala = steps; vestibuli = forecourt), and the scala tympani (Latin tympanum = drum). Both of these cavities are filled with a somewhat 27
Page 4 and 5: 1 st English edition 1999 2 nd Expa
Page 6 and 7: Contents Foreword .................
Page 8 and 9: Foreword What would you expect from
Page 10 and 11: Part 1: Man - an ingenious construc
Page 13 and 14: The eye - our window to the outside
Page 15 and 16: the inside of the eyeball. It conta
Page 17 and 18: ➨ ➨ ➨ not mean that we can se
Page 19: eyes. There will be no more death o
Page 22 and 23: Malleus Head Long (lateral) process
Page 24 and 25: amplitudes. The pressure exerted by
Page 28 and 29: less viscous liquid, called the per
Page 30 and 31: The sense of smell - beyond words F
Page 32 and 33: finest detail, using plenty of imag
Page 35 and 36: The sense of taste - not just for c
Page 37: self will serve believers as his gu
Page 40 and 41: A section of human skin. The layers
Page 42: 3 In addition to sweat, the skin al
Page 46 and 47: Heaven: a) Heaven is a place where
Page 49 and 50: The heart - more than a high-tech p
Page 51 and 52: from the heart via the arteries. Th
Page 53 and 54: Foetal circulatory system. Neonatal
Page 55: “shunted on a siding” as far as
Page 58 and 59: 6 Transportation of hormones: The b
Page 60 and 61: One cell contains 32 pg (1 picogram
Page 62 and 63: each case. We can only stand amazed
Page 64 and 65: The Bible and blood: Having explore
Page 67 and 68: The kidneys - marvels of filtration
Page 69: ➡ ment, followed by the thin loop
Page 72 and 73: The cells - our body’s 100 millio
Page 75 and 76: DNA - information storage technolog
Page 77 and 78:
total anatomy and physiology of a h
Page 79:
The structure of the DNA molecule:
Page 82 and 83:
Neurons are the building blocks of
Page 84 and 85:
municate, to evaluate, and to be cr
Page 86 and 87:
Motor cortex - body movements The
Page 88 and 89:
The fact that Archimedes had hands
Page 91 and 92:
Body, soul, and spirit - man is mor
Page 93 and 94:
a) A small cube lies in the corner
Page 95 and 96:
MAN’S STRUCTURE Monism Dualism Tr
Page 97 and 98:
explained in terms of a technologic
Page 99 and 100:
What is man? Having learned of the
Page 101 and 102:
Genesis 1:28: “God blessed them a
Page 103 and 104:
TEKEL, PARSIN. This is what these w
Page 105 and 106:
with Abraham (Gen 15:7-21, 17:3-14)
Page 107 and 108:
Does God also have sense organs? We
Page 109 and 110:
109
Page 111 and 112:
Every person - known to God? Job sa
Page 113 and 114:
- a distorted image evolutionary th
Page 115 and 116:
A very special man: Jesus Today man
Page 117 and 118:
117
Page 119 and 120:
All unbelief is sin, as we read in
Page 121 and 122:
water here will soon be death’s p
Page 123 and 124:
single set yet constructed, Cameron
Page 125 and 126:
en, but only he who does the will o
Page 127 and 128:
engines and at 7.16 metres diameter
Page 129 and 130:
Personal testimonies: Jesus found t
Page 131 and 132:
friends whom I could consult. The b
Page 133 and 134:
133
Page 135 and 136:
Getting your name in the “Book of
Page 137 and 138:
sheep... I am the good shepherd; I
Page 139 and 140:
to make sure that the entire Word o
Page 141 and 142:
Beloved of God Today many people al
Page 143 and 144:
Man in heaven: sharing the glory of
Page 145 and 146:
On the third of June 1998, possibly
Page 147 and 148:
something special. The first night
Page 149 and 150:
The Empress Elisabeth of Austria, b
Page 151 and 152:
Jesus prays to His Father in John 1
Page 153 and 154:
153
Page 155 and 156:
© Copyrights and acknowledgements:
Page 157:
157
show all

Our sense organs 45

Create successful ePaper yourself

Delete template?

Save as template?